NOTE: Using robot software to mass-download the site degrades the server and is prohibited. See here for more.
Find The PC Guide helpful? Please consider a donation to The PC
Guide Tip Jar. Visa/MC/Paypal accepted.

The 80386SX is a "lite" version of the 80386DX chip. It uses only a 16-bit
data bus, the same external bus width as the 80286. It also only can address 16 MB of
memory, like the 80286. The SX version of the 386 chip was in fact released well after the
DX, and in some ways was intended to move the market away from the 286 since it had
roughly the same interfaces but better performance. It was actually introduced several years
after the DX.

Note: It is a common myth
that the 80386SX can be substituted in place of an 80286 in a 286 motherboard. While the
chips are compatible in terms of their external interfaces they use different packaging. A
386SX could be put into a 286 motherboard if a proper adapter were used.

The narrower data bus width of the 386SX creates a reduction in performance of about
20-25% compared to an equivalent-speed 386DX; a significant difference but not excessive.
The 80386SX chip was a popular choice for the first small notebook computers, especially
the 386SL variant that introduced the SMM power management features to the Intel line. The
386SX is still a 32-bit processor internally and will run 32-bit software (really slowly
:^) ). It is available in speeds from 16 to 33 MHz; a 40 MHz version was not produced for
the SX, and is also available in cloned versions from AMD and Cyrix.